Pressure controlling device for gasoline pumps



Jan. 7, 1936. D. M CORMICK PRESSURE CONTROLLING DEVICE FOR GASOLINE PUMPS v Filed Aug. 15, 1934 Patented Jan. 7, 1936 UNITED STATES PATENT OFFICE PRESSURE CONTROLLING DEVICE FOR GAS OLIN E PUMPS My invention relates to pressure control means for liquid dispensing apparatus and more particularly to an arrangement adapted to compensate for excessive pressures due to expansion 15 in gasolin'e pumps.

In conventional gasoline pumps, it is well known that the pressure line, including the visiglass', meter unit, discharge base and associated pipes, and connections remain filled with gasoline after a quantity of gasoline has'been dispensed. The are generally exposed to atmosphericteinperature and since gasoline has a high ooelficieht of expansion, it readilyexpands when subjected to the temperature differential existing between the comparatively cool zone which gasoline is storedand the atmospheresurrounding the pump. If the pumps are exposed to the sun, and they usually are, according to present practice in connection with the '20 dispensing of gasoline at service stations, the

rate of expansion is considerably increased.

When the temperature of the gasolineis raised to that of the atmosphere and the gasoline ex- 7 pands, there is a corresponding increase in pressure which is transmitted directly to the pressure line. The resultant increase. in pressure is of such magnitude that it frequently causes breakage in some part of the pressure line; there isalso considerable danger because of the fire hazard as the result of leakage of gasoline in and around the ump unit.

It will be appreciated that the expense, incident to the servicing of pumps which are rendered inoperative because of breakage in the pressure line due to expansion of the gasoline, is of considerable importance. The unit cannot be used while repairs are being made and even after it is placed in working order again the parts are still exposed to excessive pressures developed by 40 the expansion of the gasoline. H

Heretofore, it has been proposedto control or compensatefor the expansion of the' gasoline by means of vents and float valves inserted in various positions in the pressure line. It has also been suggested to use an expansion chamber or storage tank associated with the pressure line adapted to prevent excessive pressure from developing in the system, however, the prior art devices, insofar as I am aware, fail to. provide '50 a satisfactory and economical arrangement to prevent increased pressure in the pressure line of gasoline pumps.

According to inv invention means are provided for automatically and instantaneously re- 55 leasing the pressure from the pressure line of a gasoline pump, caused by the expansion of the gasoline. The expansion eliminator is easily and quickly applied to conventional pumps and does not interference in any way with the normal operation of the pump when it is desired to dis- 5 pense gasoline therefrom.

An object of the invention is to providean improved pressure control arrangement for gaso-. line pumps wherein pressure due to the expansion of the gasoline is automatically relieved. 10

Another object of the invention is to provide an expansion eliminator for gasoline pumps, by means of which any increase in the normal pressure of the pump due to expansion of the gasoline is automatically and instantaneously re- 15 duced.

Yet another object of the invention is to provide an improved expansion eliminator for gasoline pumps wherein gasoline which is withdrawn for the purpose of relieving the pressure is re- 0 turned to the system when the pump is operated, for dispensing purposes.

Stillanother object of the invention is to provide a pressure control device for gasoline pumps, which is strong and sturdy in construc- 25 tion, consisting of butfew parts and not liable to get out of order even after long and continued use.

With these and other objects in view, which may be incident to my improvements, the invention consists in the parts and combinations to 3 be hereinafter set forth and claimed, with the understanding that the several. necessary elements, comprising my invention, may be varied in construction, proportions and arrangement, without departing from the spirit and scope of 35 the appended claims.

In order to make my invention more clearly understood, I have shown in the accompanying drawing means for carrying the same into practical effect, without limiting the improvements in their useful applications to the particular constructions, which for the purpose of explanation, have been made the subject of illustration.

In the drawing:

Figure 1 is an elevational view showing my 45 improved expansion eliminator associated with a gasoline pump unit.

Fig. 2 is a sectional view of one of the valve structures used in connection with the expansion eliminator; and

Fig. 3 is a perspective view of a check valve.

Referring to the drawing and more particularly to Figure 1 thereof, there is shown a gasoline pump unit comprising a base. I, a support casing 2, and a cover or top 3. Within the casing there is mounted a suitable pump designated generally by numeral 4 which is connected by means of a fitting 5 to a supply pipe 6 associated with a liquid storage tank I. The discharge side of the pump is connected through medium of suitable pipes, forming a discharge line to the visi-glass 8, from which the liquid passes to a discharge hose 9. Intermediate the discharge side of the pump and the discharge hose, there is mounted a metering device, not shown, for measuring the quantity of gasoline dispensed.

In the operation of the pump unit, so far described, when the outlet ,valve on the discharge end of the hose is closed, a slight pressure occurs in the discharge line and this pressure increases if the pump continues to operate. After the pressure reaches a certain value, a bypass valve in the pump unit or the valve applied to the loading or dispensing line, opens and permits the gasoline to revolve through the system and back through the pump. In order to maintain sufiicient vacuum or suction on the unit, the bypass must be provided with a suitable spring action sufficient to close the valve when the pump is stopped, so that there is always a positive working pressure on the unit. When gasoline withdrawn from the storage tank 15 permitted to stand in the pump exposed to the atmosphere, the body of gasoline in the meter unit, the visi-glass, and in all of the as-. sociated pipes and discharge hose, expands due to the temperature differential. The increased pressure caused by the expansion of the gasoline causes damage to the gaskets, the discharge hose and associated fittings, and tends to seep through packing nuts placed between the various connections.

In order to reduce the pressure in the discharge line and prevent damage to the pump caused by the breakage of any of the vital parts, I have provided an expansion eliminator comprising an overflow connection l0 in the term of a pipe connected between the discharge side of the pump 4 and the visi-glass 8. Pipe I0 is connected to the top of the glass 8 and is provided with a valve ll, normally in the open position, connected directly to the top of the glass and a check valve l2 near its connection to the suction side of the pump. Intermediate the ends of the tube, the pipe is coiled as at l3 to. provide a storage space for any gasoline which may overflow from the visi-glass.

In the operation of the device, assuming that the pump is at rest, increased pressure, due to the expansion of the gasoline which remains in the metering unit, the visi-glass and the discharge line including the discharge hose, forces gasoline from the visi-glass up through valve H and into the overflow tube Hi. When the pump is operated to dispense gasoline, valve l l is cl sed and valve I2 is opened whereby the gasoline which has overflowed into the tube and is contained in coiledportion i3 is withdrawn into the pump. As soon as the pump stops, the

valve I2 is closed and valve H is opened.

Referring to Figure 2, I have shown a detail view of valve ll, comprising a body portion l4 having a valve stem l 5 slidably mounted therein. It will be noted that the stem I5 is of slightly smaller diameter than the opening l6 formed in the body portion of the valve and that the endoif the body portion is recessed as at l! to form a seat for the head of the valve l8, The body of the valve is threaded as at [9 and 2%], portion 20 being adapted to thread into the top of the visi-glass and portion [9 being arranged to receive a fitting 2!, whereby the pipe Ill is connected to the valve. It will be noted that when the pump is at rest, that the valve stem E5 of valve II is in its lowermost position and the space It between the stem of the valve and the body portion 20 allows passage of gasoline from the glass to the overflow tube I0.

Referring to Figure 3, I have shown a view of the check valve l2 which is mounted between the suction side of the pump and the connection to the overflow tube ID. This valve is of conventional construction and comprises a body portion 22 having a pivoted flap 23 adapted to open when a suction is applied to connection 24 when the pump is operated.

While I have shown and described the preferred embodiment of my invention, I wish it to be understood that I do not confine myself to the precise details of construction herein set forth, by way of illustrations, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

In the claims:

1. In a liquid dispensing apparatus, including a pump, a source of liquid supply, and a discharge line for the liquid, a pressure control device comprising a tube between the discharge line and the suction side of the pump, said tube being formed with a coiled portion to accommodate the overflow liquid, a valve means attached to one end of the tube to control the flow of liquid thereto and separate valve means at the other end of the tube to control the flow of said liquid to the pump.

2. In a liquid dispensing apparatus, including a pump, a source of liquid supply, and a discharge line for the liquid, a pressure control device comprising a tube between the highest point on the discharge and the suction side of the pump, said tube being formed with a coiled portion to accommodate the overflow liquid, the tube being provided with a valve to control the flow of liquid thereto and a separate valve to control the flow of said liquid to the pump.

3. In a liquid dispensing apparatus, including a pump, a source of liquid supply and a discharge line provided with a visi-glass, a pressure control device comprising a tube connected between the top of the visi-glass and the suction side of the pump, said tube being provided with valve means to control the fiow of liquid thereto from the glass and separate valve means to control the flow of said liquid to the pump.

4. In a liquid dispensing apparatus, including a pump, a source of liquid supply and a discharge line provided with a visi-glass, a pressure control device comprising a tube connected between the top of the visi-glass and the suction side of the pump, said tube being formed with a coiled portion to accommodate the overflow liquid, a valve means attached to one end of the tube to control the flow of liquid thereto, and separate valve means at the other end of the tube to control the flow of said liquid to the pump.

5. In a liquid dispensing apparatus, including a pump, a source of liquid supply, and a discharge. line for the liquid, a pressure control device comprising a tube between the discharge line and the suction side of the pump, said tube being formed with a coiled portion to accommodate the overflow liquid, a valve attached to one end of the tube to control the flow of liquid thereto, said valve being normally in the open position and a second valve at the other end of the tube to control the flow of said liquid to the pump, said second valve being normally in the closed position, the first mentioned valve being adapted to close and said second mentioned valve being adapted to open whereby the overflow liquid is withdrawn from the coiled portion of the tube when the pump is operated to dispense liquid.

6. In a liquid dispensing apparatus, including a pump, a source of liquid supply and a discharge line provided with a visi-glass, a pressure control device comprising a tube connected between the top of the visi-glass and the suction side of the pump, said tube being provided with a valve to control the flow of liquid thereto, said valve being normally in the open positionand a second valve .to control the flow of said liquid to the pump, said second valve being normally in the closed position, the first mentioned valve being adapted to close and said second mentioned valve being adapted to open, whereby the overflow liquid is withdrawn from the tube when the pump is 10 operated to dispense liquid.

DAVID MCCQRMICK. 

